Hi all, I'm looking to set my arp timer to 420s and my cam table timer to 480 to get rid of unicast flooding. Anyone have any insight into the effect this will have on existing traffic? Does the switch accept the new timers gracefully or does it flush the tables and have to re-arp or re-broadcast to learn everything again.
Need to see whether this is something that needs to be done in a defined maintenance window or at any time.
Thanks in advance.
All of the arp entries above the new timeout will be re-arped.
Considerations, that I can recall...
LOWER the ARP timeout:
At the moment the timer expires, the router will ARP for the IP address. In a huge network you will see more frequent arp activity but it will flush a lot faster the devices that were removed/shut from the network which is good.
Lower the CAM: in this case you are only reducing the timeout on 20sec which won't hurt the default behavior of the switch.
I always lower the ARP timer instead of increasing the MAC in order to avoid the unicast flooding problems